1. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem1 GLAST Large Area Telescope: AntiCoincidence Detector (ACD) Subsystem WBS: 4.1.6 David J. Thompson Thomas E. Johnson NASA Goddard Space Flight Center Subsystem Manager/Instrument Manager David.J.Thompson@nasa.gov Thomas.E.Johnson@nasa.gov Gamma-ray Large Area Space Telescope

2. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem2 Overview Section 11-1 Gamma-ray Large Area Space Telescope

3. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem3 ACD Organization Chart ACD Systems Engineering 4.1.6.1.2 Mike Amato, Lead Tile Shell Assembly 4.1.6.3 Ken Segal, Lead Base Electronics Assembly 4.1.6.4 Glenn Unger, Lead Micrometeoroid Shield / Thermal Blanket 4.1.6.5 Tom Johnson, Lead Carlton Peters, Thermal Lead ACD Design and Science Support 4.1.6.1.3 Alexander Moiseev,Lead Tile Detector Assemblies 4.1.6.3.2 A. Moiseev, Lead ACD Reliability and Quality Assurance 4.1.6.2 Ron Kolecki, Lead Hardware Integration & Test 4.1.6.7 Jim La, Lead Mission Integration & Test Support 4.1.6.9 Bob Hartman, Lead Ground Support Facilities & Equipment 4.1.6.B Jim La, Lead LAT Instrument Integration & Test Support 4.1.6.8 Jim La, Lead ACD management 4.1.6.1 Tom Johnson, Manager Deanna Adamczyk - Financial Resources Andy Eaker - Scheduling ACD Subsystem 4.1.6 Dave Thompson, Subsystem Manager

4. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem4 ACD Team Partners –Micrometeoroid Shield Design – Johnson Space Center NASA Center of Excellence for micrometeoroid protection Eric Christiansen and Jeanne Crews –Tile Detector Assemblies – FermiLab (Department of Energy) Experts in fabrication of scintillator detectors Phyllis Deering and Todd Nebal –Scintillating Fiber Ribbons – Washington University, St. Louis Leaders in scintillating fiber production Professor Robert Binns –ASICs - Stanford Linear Accelerator Center (SLAC) Extensive experience in ASIC design Gunther Haller, Oren Milgrome, Dietrich Freytag

5. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem5 ACD Overview TILE SHELL ASSEMBLY –89 Plastic scintillator tiles (8.6 m 2 total) –Waveshifting fiber light collection, with clear fiber light guides for long runs (6.7 km total) –Two sets of fibers interleaved for each tile –Tiles overlap in one dimension –8 scintillating fiber ribbons cover gaps in other dimension (not shown) –Supported on self-standing composite shell –376 composite flexures support tiles –Covered by thermal blanket + micrometeoroid shield (not shown) BASE ELECTRONICS ASSEMBLY –194 photomultiplier tube sensors (2/tile) –12 electronics boards (two sets of 6), each handling up to 18 phototubes. Two High Voltage Bias Supplies on each board. –24 electrical interface connectors (1600 pins total) Base Electronics Assembly (BEA) Tile Shell Assembly (TSA) LAT Grid – Mechanical/Thermal Interface to LAT

6. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem6 ACD Changes Since PDR Light Collection –Fibers were re-routed to shorter paths to minimize losses. –Use of fiber connectors and clear fibers was optimized. –The top center row of tiles was thickened to give more light. –Tile overlaps were increased to allow for vertical gaps required by acoustic loads. –A triple layer (had been two) of square 1.5 mm fibers with offset centers was adopted for the ribbons, to increase efficiency. Mechanical –Mechanical design was optimized to meet all environmental requirements, including new orbital debris model. –A trade study for improving the light-tightness of the phototube housing was conducted, and a new design was developed. Electrical –In order to improve reliability, a redundant High Voltage Bias Supply was added to each electronics card. –The ASIC and electronics card designs are being finalized, correcting some deficiencies from earlier versions.

7. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem7 ACD Technical Heritage Plastic Scintillator - used in all previous gamma-ray telescopes OSO- 3, SAS-2, COS-B, CGRO (all 4 instruments), plus many cosmic ray experiments. Waveshifting fibers - used in GLAST LAT Balloon Flight Engineering Model (BFEM). Waveshifting bars used by HEXTE on RXTE (same material in a different geometry) Photomultiplier tubes - used in all previous gamma-ray telescopes. HEXTE/RXTE used a commercial version of the same tube we are using (Hamamatsu 4443), and GOLF on SOHO used the same tube as the ACD except for the cathode material (Hamamatsu 4444) High Voltage Bias Supplies - used in all previous gamma-ray telescopes, plus many cosmic ray experiments. Electronics - experienced ASIC designers. Discriminators, PHA and logic signals similar to many flight instruments. Micrometeoroid Shield - Improved version (more layers, stronger materials) of shield that protected EGRET successfully for nine years.

8. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem8 ACD Tile Detector Assembly (TDA) Scintillator tile/Waveshifting fibers Optical connector/Clear fibers Phototube/Resistor Network Flight-design TDAs have been successfully built, performance–tested, mounted on a flight-like composite structure, and environmentally tested to qualification levels (vibration and thermal vacuum). The TDAs are the basic detector units for the ACD

9. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem9 Tile Detector Assemblies 11/03 Shell 07/03 Subassembly ASIC 10/03 Development High Voltage Bias Supply 01/04 Photomultiplier tubes 11/03 Front End Electronics Card Assembly 01/04 Base Frame 09/03 Subassembly Base Electronics Assembly 02/04 ACD Integration 03/04 Tile Shell Assembly 12/03 ACD Performance and Environmental Test 07/04 Thermal Blanket Micrometeoroid Shield 03/04 Completion Dates Shown ACD Work Flow Overview Ship 08/04 Tile Shell Assembly (TSA) Base Electronics Assembly (BEA) Electronics Chassis 01/04

10. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem10 ProtoFlight Development Flow Due to a project de-scope, the ACD does not have an ETU. Engineering units will be built for several critical subassemblies. Development Unit Phase DesignFabTest DesignFabTest Phase DesignFabTest Flight Environmental Testing ProtoFlight Level Environmental Testing Qualification Level Peer Reviews Peer Reviews Dev Unit Mods folded into Engineering Units Design Requirements Review Eng Unit Mods folded into Flight Design Pre-Fab Review Manufacturing Readiness Review NASA GSFC - GLAST ACD Engineering Unit Phase Flight Unit Pre-Environmental Review

11. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem11 ACD CDR RFA Responses Of the 19 Requests for Action (RFA), only two involved the actual design of the ACD (micrometeoroid shield, details of mounting the long bottom tile). Other RFAs involved testing, risk, spares plan, contamination, product assurance, GSE, and schedule. 17 of the 19 are now closed (and we expect the other two to be complete soon). Sample responses are shown on the next chart.

12. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem12 RFA Responses (samples) ID #StatusRFA DescriptionRFA Response/Closure Plan ACD- 11 Open Provide correct standard for FREE rigid-flex Printed Circuit Board Specification is being written by the LAT Parts Engineer, Nick Virmani ACD- 13 Open Describe problem reporting and corrective action system. Documentation of the existing system is being written by Ron Kolecki, Systems Assurance Manager. ACD- 14 Closed Provide the ACD spares plan ACD-PLAN-000125, ACD Spares Plan, is now in the ACD Configuration Management system ACD- 15 Closed Evaluate mounting for the long bottom tile that does not involve stick-slip design. New design is similar to the flexures used for mounting the other tiles, not a stick-slip approach. ACD- 18 Closed Document the QA plan for work at Fermilab ACD-PROC-00059, Fabrication and Assembly Procedure for the ACD Tile Detector Assembly (TDA), includes the Fermilab QA plan.

13. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem13 CDR Subsystem Status Summary Final Design Established With Known Closure Plans For Design Trades –Light-tight phototube housing design - ECD: 5/30/03 –Suitability of recently-delivered ASICs for flight – ECD 5/23/03 Internal & External Interfaces Established –ICD and IDD signed, outline drawing in progress – ECD: 6/5/03 Performance Analyses Show Compliance Including Sufficient Design Margin Qualification & Verification Plans In Place Subsystem Risk Areas Identified And Mitigation Plans Established Cost & Schedule Manageable –$720K (12%) cumulative variance with recovery plans established –2 month Schedule Float to Flight Delivery Need Dates

14. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem14 Gamma-ray Large Area Space Telescope Requirements Section 11-2

15. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem15 Level III Key Requirements Summary Reference: LAT-SS-00016

16. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem16 Flowdown - Requirements to Design Particles seen in ACD Backsplash/ noise

17. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem17 Gamma-ray Large Area Space Telescope Design Section 11-3

18. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem18 Shell, Tile Detector Assemblies (TDA) & Tile Shell Assembly (TSA) Mounting the TDAs and ribbons on the shell forms the TSA Composite Shell ACD Assembly Overview Tile Detector Assembly (89)

19. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem19 ACD Assembly Overview Base Frame Assembly Electronics Chassis (12) – Phototubes, FREE Cards, HVBS LAT Grid – Mechanical/Thermal Interface to LAT Electronics Chassis, Base Frame, and Base Electronics Assembly (BEA) Mounting the Electronics Chassis into the Base Frame Assembly forms the BEA

20. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem20 ACD Assembly Overview Tile Shell Assembly (TSA), Base Electronics Assembly (BEA), and ACD Mounting the TSA onto the BEA forms the complete ACD

21. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem21 Top & Side Panels –Facesheets: 20- mil M46J/EX1522-2, [0/45/90/-45] S –H/C Core 3.1 PCF, 5056, 1”-Thick Sides, 2”-Thick Top –Film Adhesive: FM 73M, 0.045 PSF –Core fill: EY3010, Syntactic Epoxy Panel-to-Panel Joints –Mortise & Tenon (Tab & Slot) Features on Mating Edges of Panels –20-mil Internal & External Clips: Braided Tape Wetted with EA9396 –Edge Bonds: EA 9394 Adhesive Flexure Inserts –6061 External Channel/Block Post Bonded with EA9309 Shell Design

22. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem22 Tile and Blanket/Shield Mount Design

23. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem23 BFA Design BFA connection to LAT Grid Connected in 4 corners, each with 3 fasteners and a shim. Registration to LAT Grid is planned via a pin and slot common to both the BFA and the LAT Grid. BFA Corner LAT Grid Shim

24. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem24 BFA Design BFA connection to LAT Grid At each of 4 mid-span locations 2 fasteners and slip fit pin Gap Between ACD and LAT Grid is taken up with adjustable snubbers. Pin match drilled to LAT Grid after BFA is completed. Pin is captured to accommodate slip fit. Jam Nut Snubber Fastener Washers Pin Mid Span Shell Flexure

25. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem25 FlexureBlade Transverse Shear (Failure Mode of Core @ Flexure Location) Shell Flexure Insert Block to Facesheet Bond Corner +1.47+0.1 (w/potting)+0.54 Mid- Span +0.52+0.3 (w/o potting)+0.17 FlexureBlade Transverse Shear (Failure Mode of Core @ Flexure Location) Shell Flexure Insert Block to Facesheet Bond Corner+1.44+0.16 (w/potting)+0.05 Mid- Span +0.95+2.36 (w/o potting)>20.0 Margin of Safety Summary Static Thermal Tile Shell Assembly

26. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem26 Margin of Safety Summary TDA and its Interfaces

27. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem27 Margin of Safety Summary Base Frame Assembly and Chassis

28. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem28 Electrical Subsystem Topology

29. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem29 Electrical Interface 24 identical robust circular connectors (38999, series 2) & 2 circular housekeeping connectors (38999, series 2) Parts, pin outs, signal def, grounding all defined in ICD DATA PRODUCTS (defined in Reqs. and specified in ICD) Channel specific charged particle VETOs VETO hit maps Pulse Height Analysis (PHA) Diagnostics Housekeeping (thermistor output, voltage monitor output, direct to AEM) DATA PRODUCTS (defined in Reqs. and specified in ICD) Channel specific charged particle VETOs VETO hit maps Pulse Height Analysis (PHA) Diagnostics Housekeeping (thermistor output, voltage monitor output, direct to AEM)

30. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem30 Electronics Component Design Verification ASICs to be tested & screened with a separate bench-top test station at GSFC Maxim 145 and Maxim 5121 will be screened at NRL and delivered to GSFC Maxim 494 to be screened by GSFC Front-end Electronics boards to be performance and environmental tested at GSFC prior to integration with ACD High Voltage Bias Supplies to be performance and environmental tested at GSFC prior to integration with ACD Photomultiplier Tubes will be screened by a flight-approved vendor and tested at GSFC prior to integration with ACD Biasing Resistor Networks will be performance and environmental tested at GSFC prior to integration to ACD –Level IV Requirement 5.12 Radiation Tolerance. The ACD electronics shall remain within specifications after a total ionizing radiation dose of 4.5 kRad(Si). –Level IV Requirement 5.12.1 Single Event Upset Tolerance. A single event upset (SEU) shall not cause the ACD electronics to transition to an unsafe state. –Level IV Requirement 5.12.2 Latchup Tolerance. Parts that show any SEE’s at an LET lower than 37 MeV*cm 2 /mg shall not degrade the mission performance.

31. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem31 GAFE (Analog ASIC) Testing GAFE v2 testing (ACD-PROC-000067) and test report (ACD-RPT-000073) are complete. –Demonstrated GARC-to-GAFE digital core interface –Demonstrated GAFE-to-PMT subassembly interface –Met noise and Integral non- linearity requirements –Inadequate buffers made GAFEv2 unacceptable Test procedure was updated for use in GAFEv4 testing. GAFEv4 testing in progress; GAFEv5 just delivered, testing started. Radiation testing planned for GAFEv5 GAFEv4/v5/v6 4-channel test board

32. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem32 GARC (Digital ASIC) Testing GARCv1 fully tested. GARCv2 just delivered, testing started. Test report details available (ACD-RPT-000073) Identified 9 issues with GARCv1. All were straight-forward and simple fixes to a good design. GARCv2 has one known (not fatal) problem. GARC test procedure is developed and is being used to test GARCv2 GARC test board

33. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem33 Front End Electronics Board (FREE) GARCGAFEs Engineering model FREE card tested with GAFEv4 and GARCv1 Demonstrates functionality of the system Minor improvements being incorporated into the flight design Full FREE card testing will be done with GAFEv5 and GARCv2, just delivered.

34. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem34 Electronic Bread Board Test Results Sample & Hold VETO Generation Test with PMT Demonstrated ACD to LAT interface Demonstrated GARC to GAFE communication Demonstrated PMT signal processing Demonstrated VETO and HLD processing

35. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem35 High Voltage Bias Supply (HVBS) Engineering Unit HVBS currently in testing Performance meets requirements over expected temperature range

36. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem36 ACD Thermal Design Configuration Tracker Towers ICD BOUNDARY Grid Tile Shell Assembly MLI Blanket/Micrometeoroid Shield Base Electronics Assembly ICD BOUNDARY Radiation to Space Solar Flux Earth IR Albedo

37. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem37 Thermal Analyses Assumptions Orbital Analysis Thermal Environment Design Parameters Optical properties

38. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem38 Thermal Design Results All temperatures in ºC Predictions shown are raw predicts and margin does not reflect 5 ºC analytical uncertainty

39. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem39 Drawings and Parts ACD Drawing Tree (GE 2054502) – 100 drawings –47 Completed – 9 In progress –All hardware has been modeled EEE parts –ASICs not yet completed –All other parts are approved by Parts Control Board, in testing, or waiting for information Mechanical parts and materials –All approved

40. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem40 Gamma-ray Large Area Space Telescope Verification Program Section 11-4

41. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem41 ACD Requirements and Verification Tracking GLAST LAT Budgets GLAST LAT Science and Mission Requirements ACD Requirements (direct and derived) Subsystem Level Tests and Procedures GLAST LAT Verification Plan ACD Verification Plan Subsystem Level Tests and Procedures Testing Analysis & Inspection Tracking Testing Analysis & Inspection Tracking Allocation NASA GSFC - GLAST ACD

42. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem42 ACD Verification Database ACD Verification Tracking Database ACD-LAT ICD Requirements and Verification Database ACD-LAT ICD Requirements and Verification Database Links between Requirements ACD has created a Verification database in DOORS linked to the Requirements Database to Track Verification (Verification Plan - ACD-PLAN-000050) ACD Level III and IV Requirements Database ACD Level III and IV Requirements Database ACD Test Databases ACD Test Databases ACD Allocation Tables ACD Allocation Tables

43. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem43 Performance Testing - Efficiency Demonstration This approach also determines margins and relative importance of the contributors to the entire efficiency measure the performance for active elements (tiles, fiber ribbons) measure the characteristics of passive elements (WLS and clear fibers) measure values for dead areas (gaps) put everything in the simulation code to determine the resulting efficiency check the results by measuring the efficiency directly in several areas of ACD and comparing with that obtained by simulations The approach:

44. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem44 Active elements performance - TDA (LAT-TD-00843-D1) Efficiency measurement setup: M1, M2 - hardware trigger scintillators S1, S2, S3 - software trigger scintillators T1, and T2 - tested TDA’s  M1 S1 S2 T1 T2 S3 M2 Measure the light yield and efficiency for the Fermilab-made TDA prototypes (T1 and T2) equipped with clear fiber extensions and fiber- to-fiber connectors (made by GSFC) Conclusion: with one of the two phototubes operating, the TDA efficiency is slightly below the 0.9997 ACD requirement at nominal threshold; with both phototubes operating, the efficiency of the TDA meets the ACD requirement with significant margin.

45. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem45 Efficiency Demonstration – Full ACD Current gaps at -20 C o are used: between tiles - 3 mm at the top perimeter - 4 mm at the vertical corners - 4 mm vertical clearance between tiles - 2.6 mm 3-layer fiber ribbon, with light yield of 8 photoelectrons (conservative, measured) 2 cm tile overlap Light yield at PMT- 26 photoelectrons (conservative, measured) Light propagation based on measured fiber routing and connector efficiency. ACD meets the efficiency requirement even with one FREE card failed Requirement Full ACD, one FREE card failed Full ACD

46. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem46 Backsplash Measurement/Simulation Requirement Measurement ACD segmentation is based on a formula developed from 1997 beam tests at SLAC/CERN and checked with a GEANT model. Small differences among the methods were investigated at CERN in 2002. Consistent results were obtained when the calorimeter material was included in the model (Sn used to simulate CsI). The resulting backsplash is now less than originally expected, giving the ACD some margin on this requirement.

47. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem47 ACD Testing Overview Due to size and cost, there is no full-size ACD Engineering Model. The full-size mechanical mockup is used only for fit checks and fabrication of the micrometeoroid shield/thermal blankets. Acceptance and Qualification tests, including performance, vibration, EMI/EMC, and thermal vacuum, are carried out at the component and subassembly level. Extrapolation to the full ACD is done by analysis. The full protoflight ACD will undergo a complete suite of tests, including absolute efficiency measurement as well as all environmental tests. Subassembly vibration testing – a section of support shell, composite flexures supporting a scintillator tile, and a micrometeoroid shield/thermal blanket. A similar test included the waveshifting fibers, optical connector, optical fibers, and phototubes.

48. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem48 Development Environmental Testing – Tile Shell Assembly Thermal Vacuum testing – a section of support shell with composite flexures, three Tile Detector Assemblies, and four PMT/RN assemblies were exposed to 6 thermal vacuum cycles. ACD-PROC-000068, TDA-PMT-Resistor Network End-to- End Thermal-Vacuum Test Procedure Vibration testing – a section of TSA support shell, composite flexures supporting a scintillator tile, and a micrometeoroid shield/thermal blanket. A similar test included the waveshifting fibers, optical connector, and optical fibers. ACD-PLAN-000032, LAT-ACD Tile Detector Test Vibration Test Plan Vibration testing – 4 PMT/RN assemblies with clear fibers connected to 3 TDA’s (not vibrated) were subjected to vibration testing.

49. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem49 Development Environmental Testing – Development Environmental Testing – Base Electronics Assembly A section of the Base Frame Assembly – One Electronics Chassis – Two FREE boards – Four HVBS boards – Up to 36 Phototube assemblies – Mechanical structure Testing similar to that done for the TSA Engineering Model – Low-level sine – Sine burst – Sine vibration – Random vibration – Mass properties – Interface verification – Electrical functional – 12-cycle thermal vacuum Scheduled for July/August 2003 (driven by ASIC availability)

50. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem50 Test Matrix Green – Flight Yellow - Engineering

51. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem51 Test Matrix Green – Flight Yellow - Engineering

52. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem52 Top Level Environmental Test Flow (from matrix) Green – Flight Yellow - Engineering

53. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem53 Assembled ACD Environmental Test Flow EMI/EMC Vibration Test Full Functional Test Limited Functional Test Thermal Vacuum Mass Properties Acoustic Pre Environmental Review Limited Functional Test Pack & Ship Full Functional Test Setup test outlines are consistent with 568-PG-8700.1.1 Rev A 2 days 5 days 1 day 5 days Sine sweep 1 day Full Functional Test 2 days Thermal Balance 5 days 14 days 3 days 1 day 14 days Review Accelerometer data 1 day

54. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem54  Aliveness Test (AT) Functional test that turns on the ACD in a nominal state and verifies basic operation of all channels  Functional Tests  Limited Functional Test (LFT) - Test all major functions of the ACD system  Full Functional Test (FFT) - Test all functions of the ACD system except a complete measurement of all the ACD tile efficiencies  Comprehensive Performance Test (CPT) Test all functions of the ACD system and includes a complete measurement of all the ACD tile efficiencies. Requires rotation of ACD into three different orientations. Performance Tests LAT-TD-01112-D1, ACD Functional Test Plans (Comprehensive Performance Test)

55. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem55 Gamma-ray Large Area Space Telescope Fabrication Process Section 11-5

56. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem56 ACD Fabrication Plan Tile Detector Assemblies –FermiLab Scintillating fiber ribbons –Manufactured by Washington University, bent and assembled at GSFC. Composite Shell –Panel fabrication performed by outside vender, assembly and test in house Base Frame –In house fabrication, assembly and test Analog and Digital ASIC’s –GSFC/SLAC Design, MOSIS fabrication, GSFC acceptance testing High Voltage Bias Supplies –In house design, fabrication by local vender, testing in house PMT/Resistor Network Assembly –Procure components and assemble and test in house Front End Electronic (FREE) Boards –Procure components and assemble and test in house Micrometeoroid Shield/Thermal Blanket –Shield designed by JSC, Blanket designed by GSFC, In house fabrication ACD Integration and Test –Building 7, 10, 15, & 29 complex Qualification phototube in housing with resistor network.

57. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem57 Procurements Long lead procurements –Photomultiplier Tubes – Have received all 240 flight tubes –TSA Composite Support Shell – contract in place –Tile Detector Assemblies (with fibers) – fabrication started Major upcoming procurements –Base Frame –Flight Analog and Digital ASICs –High Voltage Bias Supplies –PMT Assembly Smaller upcoming procurements –Electrical components –Tile Detector Assembly mounts Tile Detector Assembly with A clear fiber connector

58. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem58 TSA Manufacturing Flow Lay-up skins Consolidate panels Thermal cycle blanks Receiving Inspection Inspect Dry fit shell Lay-up Tile Flexures Bond Tile Flexure & doublers to panels Lay-up Tile Flexure doublers Machine flexure & doublers Inspect Assemble & Bond TSA Panels Wet lay-up Corner Braids Inspect Fab. Shell Flexure fittings Bond Shell Flexure Fittings Match Drill Flexure Fittings Fit Check To BFA Inspect Machine flexure & doublers Inspect Contracted operations GSFC code 547 Inspect Inspections Receiving Inspection Receiving Inspection PANELSFLEXURES Machine panel blanks

59. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem59 Match drill to LAT GRID@ LAT Inspect Fab BFA Metallic Parts Coat Parts Assemble BFA Match drill For TSA Flexures Fit Check TSA Flexures Inspect BFA Manufacturing Flow Receiving Inspection Contracted operations GSFC code 547 Inspections

60. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem60 ACD I&T Assembly/Integration Flow Major activities in I&T flow have been defined (LAT-TD-00430-D1) Install & Test 17 Rows of TDAs and fiber cables (5 TDAs per row) TSA Subassembly Integration Complete Comprehensive Performance Test (CPT) Pre Environmental Review Install & Test a 2 nd, 3 rd, 4 th Set of 2 Electronic Chassis (FREE, HVBS, PMT) Install Fiber Ribbons On Tile Shell Receive Flight Qualified Tile Shell Receive Flight Qualified Base Frame Install & Test a Set of 2 Electronic Chassis (FREE, HVBS, PMT) on BFA BEA Subassembly Integration Complete Install TSA onto BEA, Mate & Test Fiber Cables to PMTs (186 times) Full Functional Test Mate, Install & Test last 4 long Tiles (lower TDAs) 7 days 60 days 7 days 21 days 10 days 2 days 3 days 2 days30 days1 day Install Micrometeoroid Shield & Thermal Blanket

61. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem61 Gamma-ray Large Area Space Telescope Cost and Schedule Section 11-6

62. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem62 CCB Actions Affecting 4.1.6 Change Request #DescriptionStatus LAT-XR-00770-01Additional HVBS’sApproved, $60K LAT-XR-01000-01FY01 Carryover CostsApproved, $275K LAT-XR-01001-01MPS Tax RephasingApproved, $50K LAT-XR-01009-01Scheduling SupportApproved, $82K LAT-XR-01011-01ASIC Development Support Approved, $549K LAT-XR-01119-02Revised ACD CDR DateApproved, $0K LAT-XR-01161-01Micrometeoriod Shield Design & Test Approved, $25K LAT-XR-01192-01L3 Milestone ChangesApproved, $0K LAT-XR-01200-01Mass Allocation IncreaseApproved, 45 kg LAT-XR-01750-01EGSE S/W SupportApproved, $237K

63. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem63 Tile Detector Assemblies 11/03 Shell 07/03 Subassembly ASIC 10/03 Development High Voltage Bias Supply 01/04 Photomultiplier tubes 11/03 Front End Electronics Card Assembly 01/04 Base Frame 09/03 Subassembly Base Electronics Assembly 02/04 ACD Integration 03/04 Tile Shell Assembly 12/03 ACD Performance and Environmental Test 07/04 Thermal Blanket Micrometeoroid Shield 03/04 Completion Dates Shown ACD Work Flow Overview Ship 08/04 Tile Shell Assembly (TSA) Base Electronics Assembly (BEA) Electronics Chassis 01/04

64. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem64 1st Critical Path – ASIC Development Received updated versions of ASIC’s in late April –Currently in testing –Several problems have been identified and the designs have been updated GARC ready for flight fabrication GAFE design being updated, expected to be completed by May 23 ActivityDates ASIC Design8/22/02-5/16/03 Flight Unit (FU) ASICs submitted to fabrication5/23/03 FU ASIC Development (fab, package, test, screen)5/23/03-10/9/03 FREE FU Populate w/Analog ASIC,Digital ASIC, ADC, DAC & Inspection10/10/03-10/23/03 Electronics Chassis FU Validation Testing10/24/03-1/15/04 BEA Integration1/16/04-2/13/04 Install TSA on BEA2/17/04-3/3/04 ACD Functional and Performance Testing3/4/04-4/20/04 ACD Environmental Tests4/21/04-7/2/04 Shipping to SLAC7/6/04-7/21/04 Post Ship activities7/22/04-8/10/04 Schedule Contingency8/11/04-10/25/04 ACD to LAT Integration10/26/04

65. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem65 2 nd Critical Path - Phototube/resistor network assembly Labor-intensive assembly process. Must be light tight and protected against corona for high voltage. New light-tight housing design may help. ActivityDates PMT Procurement (all 240 flight units already received)10/15/02-6/26/03 Resistor Network Flight Unit procurement, populate, assembly, & test6/18/03-11/5/03 PMT Integrate & Conformal Coating7/10/03-11/06/03 Electronics Chassis Flight Unit Pop w/PMT’s & Inspect11/7/03-11/13/03 Electronics Chassis Flight Unit Validation Testing10/24/03-1/15/04 BEA Integration1/16/04-2/13/04 Install TSA on BEA2/17/04-3/3/04 ACD Functional and Performance Testing3/4/04-4/20/04 ACD Environmental Tests4/21/04-7/2/04 Shipping to SLAC7/6/04-7/21/04 Post Ship activities7/22/04-8/10/04 Schedule Contingency8/11/04-10/25/04 ACD to LAT Integration10/26/04

66. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem66 Budget, Cost, Performance

67. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem67 Cost/Schedule Status ItemIn k$ Budget at Complete11,557 Budgeted Cost for Work Scheduled (a)7,048 Budgeted Cost for Work Performed (b)6,070 Actual Cost for Work Performed6,790 Cost Variance-720-11.9% of (b) Schedule Variance-978-13.9% of (a) Status as of March 31, 2003:

68. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem68 Gamma-ray Large Area Space Telescope Risk and Summary Section 11-7

69. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem69 ACD “Top Five” Risk Summary ID #Risk Rank Risk DescriptionRisk MitigationMitigation Status ACD- 0001 ModerateDesign flaw in flight ASIC Five foundry runs, comprehensive test program, and peer reviews. For radiation, other ASICS using this same process have been successful, and some of the LAT ASICS that are similar in design will be tested first. Contingency plan: Replace with newly designed ASICs ASICs in testing. Planning work-arounds or re-designs for aspects of the ASICS that have been deficient in earlier versions, in case additional versions are needed. SE- 0001 Moderate Requirements that the ACD must meet could change, forcing a redesign, loss of performance, or potentially loss of the ACD from inability to meet such requirements. External ACD requirements not under final signature release may change; resulting in cost & schedule impact. (1) ACD engineers and managers will keep LAT management informed immediately when new requirements seem to appear. In coordination with the LAT Systems Engineering group, we will maintain a table of open items involving requirements on the ACD. (2) LAT systems engineering will help resolve these issues in a timely fashion. Discussions are ongoing, supplemented by a list of open issues posted biweekly to the ACD Web site.

70. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem70 ACD “Top Five” Risk Summary ID #Risk Rank Risk DescriptionRisk MitigationMitigation Status ACD- 0005 Moderate Light Leak in the detector system channel Early testing & qualification of subassembly, handling procedures. Contingency Plan: Additional light wrap can also be added Plans for regular light testing and upgrades of light seals are in place. ACD- 0019 Moderate QA finds problem in part (ie GIDEP alert), or other parts problem develops (such as lead time becoming excessive). Replace with different partWatching long lead-time items closely. ACD- 013 Moderate Civil Servant test conductors pulled off for another project High visibility with GSFC management. Contingency plan: Hire & Train test conductors Goddard management has been supportive of ACD use of Civil Servants.

71. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem71 Summary The ACD continues to make technical progress. All the technical recommendations from reviews have been resolved. The ACD has developed a coherent, verifiable cost and schedule plan. We are not happy with the variances, but they are within typical contingencies for a flight project. The schedule has two months of float at the end. The ACD faces no unusual risks. The risks are those experienced by any space flight instrument. The ACD has an experienced team. The ACD is ready to proceed with flight hardware fabrication.

72. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem72 Gamma-ray Large Area Space Telescope Appendix A Requirements (some duplication of main presentation for completeness)

73. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem73 Level III Key Requirements Summary Reference: LAT-SS-00016

74. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem74 Flowdown - Requirements to Design Particles seen in ACD Backsplash/ noise

75. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem75 Tracker Calorimeter Tracker Calorimeter Charged particles produce signals lined up in the segmented ACD, TKR, CAL A high-energy gamma ray can produce secondary photons that “splash” out of the CAL and can trigger an ACD tile. If the ACD were not segmented, we would lose the valuable high-energy gamma rays that produced a back-splash signal. This self-veto reduced the EGRET efficiency at high energies by more than 50%. Charged Particle Detection vs. Backsplash

76. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem76 Meeting the Key Requirements Charged Particles (MIP) Backsplash + noise For high-efficiency MIP detection (0.9997), want a low energy threshold. For good rejection of backsplash, want a high energy threshold. A good balance between these requirements is about 0.3 of the MIP peak energy. Energy

77. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem77 Level IV Requirements Outline 5.2Charged Particle Detection 5.3Adjustable Threshold on VETO Detection of Charged Particles 5.4False VETO due to Electrical Noise 5.5High-Threshold Detection 5.6Adjustable High-Threshold 5.7Level 1 Trigger Acknowledge (TACK) 5.8Signals5.8Signals - (8 lower level requirements) 5.9ACD Performance Monitoring5.9ACD Performance Monitoring - (10 lower level requirements) 5.10High Voltage Bias Supply5.10High Voltage Bias Supply - (14 lower level requirements) 5.11PMT5.11PMT - (6 lower level requirements) 5.12Radiation Tolerance5.12Radiation Tolerance - (2 lower level requirements) 5.13Reliability5.13Reliability - (6 lower level requirements) 5.14Commands5.14Commands - (10 lower level requirements) 5.15Output Data Formats 5.16Power Consumption 5.17Total ACD Mass 5.18Environmental Requirements5.18Environmental Requirements - (11 lower level requirements) 5.19Performance Life 5.20Rate Requirement for Operation within Specification 5.21Testability 5.22Center of Mass 5.23Volume 5.24Instrument Coverage 5.25LAT to ACD Gap. 5.26Material interaction of gamma radiation (Gamma radiation due to ACD material interactions) 5.27Thermal Blanket/ Micrometeoroid Shield Areal Mass Density 5.28Gaps between scintillating tiles 5.29Light Throughput

78. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem78 ACD System Documentation RequirementsInterface Control Approved (Under CM control) Outline Drawing ACD Electrical Specification ACD-SPEC-000061 ACD Level III Requirements LAT-SS-00016 LAT Verification Plan LAT-MD-00408 ACD Performance Verification Plan ACD-PLAN-000050 ACD I&T Plan LAT-TD-00430-D1 Verification ACD Level IV Requirements ACD-RQMT-000029 LAT Level II (b) Specifications/Requirements LAT-SS-00010 ACD Calibration Plan & ACD Comprehensive Performance Test Plan Draft In Sign Off Mature Draft Incomplete-drafts LAT Contamination Control Plan LAT-MD-00404 Combined ACD-LAT Electrical, Mechanical, Thermal ICD LAT-SS-00363 ACD-LAT Interface Definition Drawing (IDD) * LAT-DS-00309 LAT Environmental Spec LAT-TD-00788 ACD Inst Science Simulations LAT Continuous Risk Management Plan LAT-MD- 00067 Development and Eng model versions ACD, Subsystem and Component procedures, test plans

79. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem79 ACD Requirements Database ACD Level III Requirement Database (DOORS ) ACD Level IV Requirement Database (DOORS) ACD-LAT ICD DOORS Database ACD-LAT ICD DOORS Database Active Links between Requirements ACD uses our Requirements Database in DOORS to Track Requirements Screen capture of level IV doors table

80. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem80 Gamma-ray Large Area Space Telescope Appendix B Fabrication (some duplication of main presentation for completeness)

81. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem81 ACD Fabrication Plan Tile Detector Assemblies –FermiLab Scintillating fiber ribbons –Manufactured by Washington University, bent and assembled at GSFC. Composite Shell –Panel fabrication performed by outside vender, assembly and test in house Base Frame –In house fabrication, assembly and test Analog and Digital ASIC’s –GSFC/SLAC Design, MOSIS fabrication, GSFC acceptance testing High Voltage Bias Supplies –In house design, fabrication by local vender, testing in house PMT/Resistor Network Assembly –Procure components and assemble and test in house Front End Electronic (FREE) Boards –Procure components and assemble and test in house Micrometeoroid Shield/Thermal Blanket –Shield designed by JSC, Blanket designed by GSFC, In house fabrication ACD Integration and Test –Building 7, 10, 15, & 29 complex Qualification phototube in housing with resistor network.

82. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem82 Procurements Long lead procurements –Photomultiplier Tubes – Have received all 240 flight tubes –TSA Composite Support Shell – contract in place –Tile Detector Assemblies (with fibers) – fabrication started Major upcoming procurements –Base Frame –Flight Analog and Digital ASICs –High Voltage Bias Supplies –PMT Assembly Smaller upcoming procurements –Electrical components –Tile Detector Assembly mounts Tile Detector Assembly with A clear fiber connector

83. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem83 TSA Manufacturing Flow Lay-up skins Consolidate panels Thermal cycle blanks Receiving Inspection Inspect Dry fit shell Lay-up Tile Flexures Bond Tile Flexure & doublers to panels Lay-up Tile Flexure doublers Machine flexure & doublers Inspect Assemble & Bond TSA Panels Wet lay-up Corner Braids Inspect Fab. Shell Flexure fittings Bond Shell Flexure Fittings Match Drill Flexure Fittings Fit Check To BFA Inspect Machine flexure & doublers Inspect Contracted operations GSFC code 547 Inspect Inspections Receiving Inspection Receiving Inspection PANELSFLEXURES Machine panel blanks

84. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem84 Match drill to LAT GRID@ LAT Inspect Fab BFA Metallic Parts Coat Parts Assemble BFA Match drill For TSA Flexures Fit Check TSA Flexures Inspect BFA Manufacturing Flow Receiving Inspection Contracted operations GSFC code 547 Inspections

85. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem85 PMT Subassembly Assembly and Test Process Assembly Plans Resistive network PCBs Populate Resistive Network QA RN test QA Assemble Resistive Network Resistive Network Assembly & Test Process PMT Test PMT rolled in mumetal PMT bonded to housing w/ Uralane Assembly Plans QA PMTs Test Plan V VV PMT Bonded Assembly & Test Process PMT & RN Assembly PMT subassembly test QA V Parylene Coat QA VV PMT subassembly Assembly & Test Process PMT subassembly test PMT Subassembly = PMT bonded assembly + PMT Resistive Network = Quality Assurance Inspection = Visual inspection V QA

86. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem86 FREE Assembly Integration and Test Flow

87. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem87 Electronics Chassis PMTs in Housings PMT resistor networks Free boards (2) PMT Rails HVBSs (under FREE brds, 2 for each brd) Power distribution board Mechanical structure BEA Connectors BEA Connectors

88. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem88 Electronics Chassis – Assembly Outline 1.Start with mechanical support 2.Attach HVBS 3.Attach FREE cards 4.Attach connector supports 5.Attach phototubes to rail 6.Attach power distribution bus to rail 7.Attach rail to mechanical support 8.Make electrical connections 9.Mount Electronics Chassis in Base Frame 10.Close out mechanical structure 2 1 4 3 6 5 7

89. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem89 ACD I&T Assembly/Integration Flow Major activities in I&T flow have been defined (LAT-TD-00430-D1) Install & Test 17 Rows of TDAs and fiber cables (5 TDAs per row) TSA Subassembly Integration Complete Comprehensive Performance Test (CPT) Pre Environmental Review Install & Test a 2 nd, 3 rd, 4 th Set of 2 Electronic Chassis (FREE, HVBS, PMT) Install Fiber Ribbons On Tile Shell Receive Flight Qualified Tile Shell Receive Flight Qualified Base Frame Install & Test a Set of 2 Electronic Chassis (FREE, HVBS, PMT) on BFA BEA Subassembly Integration Complete Install TSA onto BEA, Mate & Test Fiber Cables to PMTs (186 times) Full Functional Test Mate, Install & Test last 4 long Tiles (lower TDAs) 7 days 60 days 7 days 21 days 10 days 2 days 3 days 2 days30 days1 day Install Micrometeoroid Shield & Thermal Blanket

90. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem90 Gamma-ray Large Area Space Telescope Appendix C Peer Review RFAs

91. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem91 Peer Review RFAs

92. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem92 Peer Review RFAs (Continued)

93. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem93 Peer Review RFAs (Continued)

94. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem94 Peer Review RFAs (Continued)

95. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem95 Peer Review RFAs (Continued)

96. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem96 Peer Review RFAs (Continued)

97. GLAST LAT Project CDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967Section 11 ACD Subsystem97 Peer Review RFAs (Continued)